How can the syntax of a SQL query impact the results when using PHP's mysqli functions?

The syntax of a SQL query can impact the results when using PHP's mysqli functions if there are errors in the query. To solve this issue, it is important to ensure that the SQL query is written correctly with proper syntax. One common mistake is not properly escaping variables in the query, which can lead to SQL injection vulnerabilities. Using prepared statements with placeholders can help prevent this issue. 

<?php
// Establish a connection to the database
$mysqli = new mysqli("localhost", "username", "password", "database");

// Check for connection errors
if ($mysqli->connect_error) {
    die("Connection failed: " . $mysqli->connect_error);
}

// Prepare a SQL query with placeholders
$query = $mysqli->prepare("SELECT * FROM users WHERE username = ?");

// Bind parameters to the placeholders
$query->bind_param("s", $username);

// Set the parameter values
$username = "john_doe";

// Execute the query
$query->execute();

// Get the results
$result = $query->get_result();

// Fetch the data
while ($row = $result->fetch_assoc()) {
    echo "Username: " . $row['username'] . "<br>";
}

// Close the statement and connection
$query->close();
$mysqli->close();
?>

Keywords

SQL query syntax PHP mysqli functions impact results error types

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